We bought a 40 year old retirement condo 4 years ago which had original windows with interior storm windows. Since we have electric heat and Connecticut has the highest electric rates in the continental US, we decided to have the wndows replaced with Pella. Their installer insisted that the storms needed to be removed and that we wouldn't need them. Well, we now have moisture on the inside of 3 out of 8 windows. The service tech came this week and told us we needed to remove drapes, install a dehumidifier, etc.
We didn't need to do any of this before, we are $8k poorer, and this morning was wspecially cold and we woke up to frost on the inside of the window closest to our bed!